[tor-talk] Pluggable Transports and DPI

David Fifield david at bamsoftware.com
Sat May 14 20:29:20 UTC 2016


On Thu, May 12, 2016 at 12:19:29AM -0400, Roger Dingledine wrote:
> Do we know anything about how they decided to detect obfs4 (and what
> collateral damage they decided was acceptable there)?

No, we didn't find out how they were blocking obfs4. Justin suspects
it's not an IP blacklist because neither the default Tor Browser bridges
nor custom bridges worked. He tried setting iat-mode=1 (activating
packet timing obfuscation) on the client, and obfs4 was still detected.
We didn't have an iat-mode=1 server to test timing obfuscation in both
directions.


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